The present invention relates to apparatus for dispensing liquid soap, normally in discrete small quantities or charges. Such dispensing apparatus is used, particularly for hygienic purposes, in public or institutional washrooms or the like or wherever there are a relatively large number of different users.
One such dispenser is disclosed in my U.S. Pat. No. 4,149,573, assigned to the assignee of the present invention, and of which the present invention is an improvement. In the system of the 4,149,573 patent, a container is provided with a refill aperture which is dimensioned so that at equal pressures inside and outside said container liquid soap will flow therethrough only very slowly if at all. Thus, in refilling the container, a special squeeze-bottle type refill cartridge is used in order to force the soap through the refill aperture, the cartridge outlet being closed by a pierceable membrane which is ruptured by a piercing member adjacent to the refill aperture to permit the flow of liquid soap from the refill cartridge.
While this prior dispensing system works effectively, it has been found that an inconveniently long time is required for a serviceman to squeeze the contents of the refill cartridge into the reservoir of the dispenser. Generally quite a few squeezes of the refill cartridge are necessary in order completely to empty it, and if the serviceman does not completely empty the container, considerable soap wastage results.
Also, this prior system has the disadvantage of leaving the refill aperture and the piercing member exposed to the atmosphere and possible contamination by dust and the like between refills.
Furthermore, in the case of an opaque container, it is not possible readily to determine the amount of liquid soap left therein so as to know whether or not a refill is necessary.
Finally, the cylindrical refill cartridges are of an efficient shape for squeeze-bottle operation, but are inconvenient for storage since they entail a considerable amount of wasted space.